package cn.demoframe.test.utils;

//import java.util.Date;
import java.util.UUID;

public class UUID22 {

	/**
	 * 采用URL Base64字符，即把“+/”换成“-_”
	 */
	static private final char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_=".toCharArray();

	public static String getUUID32() {
		return UUID.randomUUID().toString().replaceAll("-", "");
	}

	/**
	 * Base64 编码
	 * @param data 数据
	 * @return 结果
	 */
	private char[] encode(byte[] data) {
		char[] out = new char[((data.length + 2) / 3) * 4];
		boolean quad, trip;
		for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {
			quad = trip = false;
			int val = (0xFF & (int) data[i]);
			val <<= 8;
			if ((i + 1) < data.length) {
				val |= (0xFF & (int) data[i + 1]);
				trip = true;
			}
			val <<= 8;
			if ((i + 2) < data.length) {
				val |= (0xFF & (int) data[i + 2]);
				quad = true;
			}
			out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];
			val >>= 6;
			out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];
			val >>= 6;
			out[index + 1] = alphabet[val & 0x3F];
			val >>= 6;
			out[index + 0] = alphabet[val & 0x3F];
		}
		return out;
	}
	
	/**
	 * 转成字节
	 * @return 结果
	 */
//	private byte[] toBytes(String u) {
//		UUID uuid = UUID.fromString(u);
	private byte[] toBytes() {
    	UUID uuid = UUID.randomUUID();
        long msb = uuid.getMostSignificantBits();
        long lsb = uuid.getLeastSignificantBits();
        byte[] buffer = new byte[16];

        for (int i = 0; i < 8; i++) {
            buffer[i] = (byte) ((msb >>> 8 * (7 - i)) & 0xFF);
            buffer[i + 8] = (byte) ((lsb >>> 8 * (7 - i)) & 0xFF);
        }
        return buffer;
    }
	
//	public String getUUID(String u) {
//		char[] res = encode(toBytes(u));
	public String getUUID() {
		char[] res = encode(toBytes());
		System.out.println(new String(res));
		return new String(res, 0, res.length - 2);
	}
	
	public static void main(String[] args) {
		System.out.println(getUUID22());
//		System.out.println(getUUID("c19b9de1-f33a-494b-afbe-f06817218d64"));
//		System.out.println(getUUID22("c19b9de1-f33a-494b-afbe-f06817218d64"));
//		Date d1 = new Date();
//		for(int i = 0; i < 1000000; i++) {
//			UUID.randomUUID().toString();
//			getUUID22();
//		}
//		Date d2 = new Date();
//		System.out.print(d2.getTime() - d1.getTime());
	}
	
	/**
	 * 将随机UUID转换成22位字符串
	 * @return 结果
	 */
//	public static String getUUID22(String u) {
//		UUID uuid = UUID.fromString(u);
	public static String getUUID22() {
		UUID uuid = UUID.randomUUID();
//		System.out.println(uuid.toString());
		long msb = uuid.getMostSignificantBits();
        long lsb = uuid.getLeastSignificantBits();
        char[] out = new char[24];
        int tmp = 0, idx = 0;
        // 基础写法
        /*tmp = (int) ((msb >>> 40) & 0xffffff);
        out[idx + 3] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 2] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 1] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx] = alphabet[tmp & 0x3f];
        idx += 4;
        
        tmp = (int) ((msb >>> 16) & 0xffffff);
        out[idx + 3] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 2] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 1] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx] = alphabet[tmp & 0x3f];
        idx += 4;
        
        tmp = (int) (((msb & 0xffff) << 8) | (lsb >>> 56 & 0xff));
        out[idx + 3] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 2] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 1] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx] = alphabet[tmp & 0x3f];
        idx += 4;
        
        tmp = (int) ((lsb >>> 32) & 0xffffff);
        out[idx + 3] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 2] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 1] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx] = alphabet[tmp & 0x3f];
        idx += 4;
        
        tmp = (int) ((lsb >>> 8) & 0xffffff);
        out[idx + 3] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 2] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx + 1] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx] = alphabet[tmp & 0x3f];
        idx += 4;
        
        tmp = (int) (lsb & 0xff);
        out[idx + 3] = alphabet[64];
        out[idx + 2] = alphabet[64];
        tmp <<= 4;
        out[idx + 1] = alphabet[tmp & 0x3f];
        tmp >>= 6;
        out[idx] = alphabet[tmp & 0x3f];
        idx += 4;*/
        
        // 循环写法
        int bit = 0, bt1 = 8, bt2 = 8;
        int mask = 0x00, offsetm = 0, offsetl = 0;
        
        for(; bit < 16; bit += 3, idx += 4) {
        	offsetm = 64 - (bit + 3) * 8;
        	offsetl = 0;
        	tmp = 0;
        	
        	if(bt1 > 3) {
        		mask = (1 << 8 * 3) - 1;
        	} else if(bt1 >= 0) {
        		mask = (1 << 8 * bt1) - 1;
        		bt2 -= 3 - bt1;
        	} else {
        		mask = (1 << 8 * ((bt2 > 3) ? 3 : bt2)) - 1;
        		bt2 -= 3;
        	}
        	if(bt1 > 0) {
        		bt1 -= 3;
        		tmp = (int) ((offsetm < 0) ? msb : (msb >>> offsetm) & mask);
        		if(bt1 < 0) {
        			tmp <<= Math.abs(offsetm);
        			mask = (1 << 8 * Math.abs(bt1)) - 1;
        		}
        	}
        	if(offsetm < 0) {
        		offsetl = 64 + offsetm;
        		tmp |= ((offsetl < 0) ? lsb : (lsb >>> offsetl)) & mask;
        	}
        	
        	if(bit == 15) {
        		out[idx + 3] = alphabet[64];
                out[idx + 2] = alphabet[64];
                tmp <<= 4;
        	} else {
	            out[idx + 3] = alphabet[tmp & 0x3f];
	            tmp >>= 6;
	            out[idx + 2] = alphabet[tmp & 0x3f];
	            tmp >>= 6;
        	}
            out[idx + 1] = alphabet[tmp & 0x3f];
            tmp >>= 6;
            out[idx] = alphabet[tmp & 0x3f];
        }
        
        return new String(out, 0, 22);
	}
}
